Railroad car truck spring cluster



July25,.1944. K. R. HAMMERsTRoM- 2,354,458

RAILROAD CAR TRUCK SPRING CLUSTER Filed Aug. 18, 1942 INVENTORz' 'K4/ez f?. HUA/MgeSr/@UM Patented `luly 25, 1944 ,UMTEDy 'STATE RAILROADy CAR TRUCK` sRIG oLUs'rE Karl R. Hammerstrom, `Pittsburgh,"la., assignor l to UnitedStates Steel Corporation of Delaware, alcorporaton of Delaware' l Application August 18, 194.?;SerialrNo.` 455,250 l 5 Claims. (Cl. 267-4) This invention relates yto railroad car truck spring clusters of the type which increases its normal resistance to deflection after deflecting a predetermined distance, forthe purpose -of improving the riding qualities of an unloaded or partially loaded car, without interfering vrwith the clusters ability tocarry a fulllload. rI he object is to provide such a cluster so that `the various spring columns are all of the same lengths regardless of whether they are free because of.

no loading, orare completely solid because of overloading, whereby the coumns may be ar. ranged parallel with all their ends naturally viiush in any conventional clustering.

Specific examples of the invention are illustrated by the accompanying drawing in which the .gures are as follows:

Figure 1 is a side view of a four-column cluster;

Figure 2 is a top view;

Figure 3 is a section from the line III--III in Figure 2;

Figure 4 is the same as Figure 3,but showing the springs fully closed; and l .v

Figure 5 is the same as Figure 2 butrshowing a five-column cluster.

More specically, the drawing shows a railroad car truck spring clusterincluding at least four parallel flush-ended columns A, B, C'and D of inner and outer nested compression coil springs I and 2 respectively made of relatively lighter andheavier springr bar each of the same weight in each instance for all the springs'malde there,-

of. In other words,vthe inner springs'l are made'j of lighter spring vbar while, .the outer'springs 2 are made of heavier spring bar, and thesprings I are all madeof the samerweightspring bar, while the springs 2 are all made of the same weight spring bar.

in the case of the springs 2 of columns C and D,v

this likewise applying to the use `of standardk spring retainer plates 3 for the purpose of laterally positioning the inner springs las in the conventional cluster, the outer springs being po# lengths, plates 3 positioning them in the conven-f tional parallel flush-ended fourL-columnclusterqf The remaining two outer springs of' the col" umns Aand B, indicated as 2a in" the drawing,`

may also follow conventional practice excepting for havingrelatively shorter free `and closed, lengths vso there are spaces of lengthsY .r 'be-- Conventional lpractice may be followed in the case of al1 the Springs I and' tween 'their ends and those of the others, these spaces containing rigid compression transmitting members 4. extending axially of the springs for lengths ry which are less than the lengths ofthe spaces and which equal the vdis-tances a between the closed lengths of the two shorter springs 2a and the closedlengths of the other springs, these other springs includingall the'inner springs I and the louter springs 2 of the columns C and D.

The members 4 are-1n the form of cylinders having segmental circular depending `flanges 4a partially encircling the top convolutions of the springs l20L so as to form :retainers engaging and: laterally positioning the adjacentends of the two shorter springs 2a, and constituting retainers rigidly associated with the members'4, the latter having inward flanges 4b against which the springs 2a bear, the other ends of these springs being flush with the adjacent ends of the other springs. The upstandingv cylindrical walls of the members4 provide the compression carrying portions,and these walls also function as spring retainers that are opposite the retainers 4a, and which engage and laterally position compression coilsprings 5 nestedv about the inner springsv I of the columns A and B having the shorter outer springs 2a. -These retainer springs 5 have free or, in *other words, these springs 5 have-free lengths bringing their other ends iiush with the adjacent ends of the columns when all the springs are free; naturally flush-ended.` At the s-ame time, the columns all have the same'solid capacities, the deflection resistancesof the springs 5 being slight since these springs function mainly to retain themembers 4fand to prevent them from rattling. In this connection, the openings 4b in the inward flanges of the meinbers-4 yare sized to embrace the linner springs I of the columns A and B, this largely relieving the springs `5 from'performing any function other than holding the members 4 in position in the case of Van unloaded or lightly loaded car. To increase the lateral stabilities of the columns A and B, the members 4 are interconnectedby a strut 4c, the two members 4 and their inter'- tegral casting. This facilitates assembly of the cluster and assures rigidity between the mem'- bers 4,` with consequently greater stability of the' cluster. In this "same interest, the strut 4c is 4d in which'the columns C and' DV nest.

In this manner all the columns areY In the case of the Figure 5 showing the application of the principles of the invention to a five-column cluster, the same numerals are used since the parts are all equivalents. The only thing that need be noted as a difference in the provision of the strut 4c with an opening through which passes the central column E of the cluster, the steadying walls 4d being provided on the inside of the hole/so that the central column E nests therein. In the case of a six-column cluster, the two central transversely opposite columns will constitute the columns A and B, with the columns on the opposite sides of these then followingconventional practice. IThis last is` not 'illustrated since there is no chance for` misunderstanding.

Assuming the illustrated cluster is in the window of a freight car truck side-frame, with the bottom plate 3 resting on the spring seat andthe bolster supported by the cluster on top of the top one of the plates 3, it can be appreciated that the cluster works in the same level manner of a conventional cluster, but` that it will have less resistance to deflection in the case of an unloaded or lightly loaded ca r, the spaces then being greater than the lengthsy of the members 4Q Increased loading results in diminishing the space lengths :r so that they ultimately equal the lengths y of the compression transmitting members 4, the springs 2a then adding their full deflection resistance to the cluster. The cluster will then l'have a greater resistance to deflection thanv a uniformly deilecting cluster; because although the springs 2 and 2a are made of the same diameter spring bar, the shorter length of the springs 2a, as compared with the springs 2, causes the same closing motion of the cluster as a unit, to causethe same deection of the springs 2a as it does of the springs 2, the springs 2a, therefore, oifering greater resistance to deflection than the springs 2. Since the springs 2a offer more resistance to deection, their effect is of real practical value and effectively increases the loading necessary to completely close the springs, so the resistance to over-- loading is enhanced.

When two coil springs are made of the same strength material and of the same outside diameter and of the same diameter spring bar they will have the same deflection and unit' carrying capacities per coil. However, if one spring is made longer, as for example, by doubling the number of coils, the load capacity would not change but the longer spring would have twice the deflection and one-half the resistance for the same deflection as the shorter spring. If one of these long springs and one short spring be arranged'side by side to carry a given load, a spacer block or equivalent must be addedto the short spring' to compensate for the difference in solid heights of the two springs. The longer spring will then carry all the load for a distance of one-half its total deflection during which movement onehalf its capacity will be utilized. For the remainder of the travel both springs will deflect in unison and the other half of the capacity of the long spring will be absorbed while all of the capacity of the short spring will be taken up in this distance, with the result that the resistance over the last half of the travel is greatly increased andr at closurev both springs carry equal load.

light retainer springs 5 which work in conjunc- -tion with springs 2a, are of relatively light capacity and, therefore, transmit only a fractional load and deflection to springs 2a up to the point where .r equals y. Therefore, to this point in the travel of the group, springs 2a oler very little resistance to deflection and the other springs are actually carrying the major part of the load, producing a relatively low resistance and consequently an easy riding vehicle up to .r equal y deflection of the group. For the balance of the `travel the two springs 2a will deilect in harmony with springs I and 2 and, due to their shorter alb.

Using-the principal of this eXample,'it will be length and the fact that little of their travel and capacity have been utilized up to this point as compared with springs 2, they will offer more resistance comparatively, so that the capacity of the group will be increased to the point where at closure the full load capacity of all springs is realized. This simple method provides softer riding for empty or partially loaded cars and stiffer resistance to deection with satisfactory riding for heavier loaded and fully loaded cars.

For the purpose of keeping the number of spring bar diameters to a minimum, this description covers springs made from bars of but two diameters. In some designs it may be desirable to vary the spring bar diameters.

I claim:

1. A railroad car truck spring cluster including at least four parallel flush-ended columns of inner and outer nested compression coil springs respectively made of relatively lighter and heavier spring bar of the same weight in each instance for all the springs made thereof, all of the inner springs and at least two of the outer springs having the same free and closed lengths with at least one of the remaining outer springs having relatively shorter free and closed lengths so there is a space between its end and those of the others, this space containing a rigid compression transmitting member extending axially of the spring for a length less than thev differences between the free length of the shorter spring and the free lengths of the other springs and equaling the difference between the closed length of the shorter spring and the closed lengths of the other springs.

2. A railroad car truck spring cluster including at least four parallel flush-ended columns of inner and outer nested compression coil springs respectively made of relatively lighter and heavier spring bar of the same weight in each instance for all the springs made thereof, all of the inner springs and at least two of the outer springs having the same free and closed lengths with the remaining outer springs having relatively shorter free and closed lengths so there are spaces between their ends and those of the others, these spaces containing rigid compression transmitting members extending axially of the springs for. lengths less than the differences between the free lengths of the shorter springs and the free lengths of the other springs and equaling the differences between the closed lengths of the shorter springs and the closed lengths of the other springs, the members being rigidly associated with retainers engaging and laterally positioning the adjacent ends of the shorter springs which have their other ends flush with the other adjacent spring ends, and the members also being rigidly associated with opposite retainers engaged and laterally positioned by retainer compression coil springs nested around the inner springs of the columns having the shorter outer springs, the retainer springs having free lengths bringing their other rends flush with the adjacent ends of the columns when vall the springs are free.

3. A railroad car truck spring cluster including at least four parallel flush-ended columns of I inner and outer'nested compression coil springs respectively made of relatively lighter and heavier spring bar of the same weight in each instance for all the springs made thereof, all of the inner v springsv and at least two of the'outer springs havspaces containing rigid compression transmitting 3 shorter springs and the closed lengths of the other springs, the members being rigidly associated'with retainers engaging and laterally positioning the adjacent ends of the shorter springs which have their other ends flush with the other adjacent spring ends, and the members also being rigidly associated with opposite retainers engaged and laterally positioned by retainer compression coil springs nested around the inner springs of the columns having the shorter outer springs, the retainer springs having free lengths bringing their other ends `ilush with the adjacent ends of the columns when all the springs are free,

' and the `respective members being rigidly intermembers extending axially of the springs for lengths less than the differences between the free connected as a unit so as to increase the lateral stability of the last named coliunns,

5; A railroad car truck spring cluster including at least four parallel flush-ended columns of inner and outer nested compression coil springs respectively made of relatively lighter and heavier spring bar of the sameweight in each instance for all the springs made thereof, all of the inner springs and at least two of the outer springs having the same free and closed lengths with the remaining outer springs having relatively shorter free and closed lengths so there are spaces beated with opposite retainers engaged and laterally positioned by retainer compression' coil` ing at least four parallel flush-ended columns of inner and outer nested compression vcoil springs respectively made of relatively lighter and heavier spring bar of the same weight in each instance for all the springs made thereof, all of the inner springs and at least two of the outer springs having the same free and closed lengths with the remaining outer springs having relatively shorter free and closed lengths so there areV spaces between their ends and those of the others, these spaces containing rigid compression transmitting members extending axially of the springs for lengths less than the differences between the free lengths of the shorter springs and the free lengths of the other springs and equaling` the differences between the' closedv lengths of the tween their ends and those of the others, these spaces containing rigid compression transmitting members extending axially of the springsl for lengths less than the differences between the free lengths of the shorter springs and the free lengths of the other springs and equaling the differences between the closed lengths of the shorter springs and the closed lengths of the other springs, the members being rigidly associated with retainers engaging and laterally positioning the adjacent ends of the shorter springs which have their other ends flush with the other adjacent spring ends, andthe membersl also being rigidly associated with opposite retainers engaged and laterally positioned by retainer compression coil springs Anested around the inner springs of the columns having the. shorter outer springs, the retainer springs having free lengths bringing their other ends flush with the adjacent ends of the columns whenr all the springs are free, and the members encircling the inner springs of the last named columnsr so as to be further laterally positioned f thereby and the respective members being rigidly interconnected as a unit so as to increase the lateral stability of the last named columns.

KARL vKR. HAMMERSTROM, 

